PHP soap客户端http标头

Question

I am trying to add clientid in http header in soap client but unable to do so. After adding the clientid I am getting empty response, when I print the header it is not showing the clientid which I am passing.

$url = "http://xxxx.xxx.xxx?getdatawsdl";


$context = array('http' =>
    array(
        'header'  => 'clientid: xxxx',
    )
);


$soap_options = array(
    'trace' => 1,
    'exceptions' => 0,
    'stream_context' => stream_context_create($context)
);

$client = new SoapClient($url,$soap_options);

I think I am not setting the header correctly therefore not getting soap response nor it is appearing in header. I am getting proper response when send request through soapui after setting the header.